Rebreathers could make an ocean explorer’s ultimate fantasies come true. Recirculating the same air again and again might sound like science fiction, but compared against traditional scuba equipment, rebreathers allow divers to go deeper, stay under longer, and get closer to wildlife. It’s everything a diver would want. So why haven’t they outright replaced scuba gear in the underwater swimming industry?

The same factors that hold back every other emerging technology: they’re still too expensive and too unsteady.

This is in spite of the fact that the technology on which rebreathers are based actually dates back to the 19th century. Today, dozens of manufacturers offer different styles of rebreathers to suit divers’ needs, and the systems keep getting cheaper, safer, and more reliable. There’s no doubt rebreather diving’s popularity is trending upward.

Yet, it’s still a fringe element on the scuba scene. While popular for technical diving, underwater videography, and military applications, rebreathers are still not part of standard training for the vast majority of divers. What gives?

Travel to the secluded Korean islands of Jeiu and Udo, and you might see a strange sight. Every morning, thousands of women take to the sea surrounding the islands to hunt for seaweed, abalones, sea urchins, and octopuses. These women, called the haenyo, or Korean Mermaids, dive up to 65 feet for their prizes, using no equipment other than goggles and wetsuits. They make these dives several times a day. And almost all of them are over the age of 60.

This "vertical cave" is a paradise for divers and photographers—and it might explain the fall of Mayan civilization.

Belize's Lighthouse Reef contains something of an anomaly: After all, when we see sinkholes on the news, they're usually disastrous and frightening, swallowing up Australian campgrounds and Florida used car lots with abandon. But let's not forget the fun, chill kind of sinkhole: the underwater kind! The Great Blue Hole of Belize, for example, is not just the most obviously named place in the world (tied for #1 with Australia's Great Sandy Desert). It's also a bucket list destination for just about every scuba diver on the planet.

Underwater: Baros has its own house reef, close enough to the shore that snorkellers can swim to it. In addition, there are 30 dive sites within an hour of Baros, all with spectacular reefs and vibrant marine creatures. And the 'Diving by Design' programme ensures that each diving experience is tailored to the individual's needs.Above water: Elegant villas sit on stilts in the water or along the island's white-sand beach. Both food and atmosphere are important here, with sunset trips on a traditional dhoni to a sandbank where guests can dine privately under the night sky.Best time to go: Underwater visibility is not as clear in the summer months when masses of plankton float here, but this in turn attracts whale sharks and manta rays.Baros: North Malé Atoll, Maldives (00 960 664 26 72;

If you plunge into the sea to ogle exotic wildlife, why not stay a while—and get an even closer view? Cave-diving engineer Bill Stone [see "Journey from the Center of the Earth," February 2007] makes that possible with the most user-friendly version yet of a rebreather, a device that recycles your exhaled air, removes carbon dioxide, and adds oxygen. (A scuba device quickly burns through tanks of fresh air.)

On a typical dive, the Poseidon Discovery lets divers stay underwater at least three times as long as scuba gear can, and since you don't exhale into the water, you don't create bubbles or noise that can scare off fish.

Military and advanced divers have used rebreathers for decades, but they're pricey rigs (about $10,000) that require extensive training on how to manually mix gases in case the gear fails. Stone's recreational model automates the safety system with built-in computers that check all components pre-dive, plus two oxygen sensors that monitor the gas mix. If the system spots an air-recycling malfunction, the mouthpiece vibrates and blinks an alert. Just flip its lever to inhale from a small fresh-air tank and return safely to the surface.

Neoprene is a synthetic rubber that's often used to make wetsuits, hence its alternative name "scuba." It's also used in electrical insulation and drum practice pads, but don't let the industrial uses scare you off. Neoprene has become increasing popular as a material to wear on the street (not just in the sea) because many of the qualities that make it great for use in factories, like stain resistance and general durability, make it great for clothing, too.

The fabric is thick and doesn't breathe, making neoprene a perfect addition to your winter wardrobe, and the thickness also allows for creation of structured pieces that look out of this world. The weight of neoprene also means form-fitting skirts and dresses are more forgiving. You'll never run the risk that your bodycon skirt or tight leggings are accidentally a little bit see-through. The material is always opaque, and its resiliency means it doesn't really stretch out. Neoprene also holds photorealistic patterns well, so it's not uncommon to see huge florals or intricate pattens splattered all over a dress or a sweatshirt. Did I also mention it's incredibly comfortable.

My Road to Instructor

Posted: Jul 11, 2016

My name is Javier Cantellops and I have loved the water since I was born. I have just recently become an Open Water SCUBA Instructor. I have also just landed an amazing job on the paradise island of Maui. This is the story of how I became an Open Water Instructor, the path I took to get to live my dreams, and my perspective on what it takes to do it. My journey was not your average one, that is for sure, but the outcome was nevertheless standard. Meaning if you want it, it can be yours.

I started my diving career as a free diver, free diving wherever I've lived.

I've explored the reefs of the Big Island, been spearfishing in Costa Rica and had always gone scuba diving with my friends along the way just for fun. I'd never had any classes, just always knew what to do and most importantly what not to do (i.e. don't hold your breath on scuba). That was pretty much all I knew.

After a wild and successful business venture in Costa Rica, and becoming absolutely hooked on diving, I decided, after long thought, that diving was what I wanted to do so we sold the business. I was 32 years old at the time and my son was three and I decided to make a change. So we moved back to the states and staged out of South Carolina, my "hometown", trying to figure out exactly what it was that I was going to do. I had just the barest ideas of what I wanted life to be about. I wanted to be in the water, I wanted to share my passion, I wanted to help people find excitement, I wanted to be an instructor...

I recently left my job as a deep sea diver. I worked for a large company that offers diving services ranging from salvage, underwater demolition, ship repairs, and search and recovery. They are a reputable company and are considered safe and reliable. So much so that they are often contracted by the government. Truth be told, I will miss working for them. The people I worked with were truly the best of the best. But there are only so many unexplainable things you can witness in the deep before you decide to stay out of the ocean forever. Here are some examples of the secrets many divers take to their graves.

The Newtown Creek, a 324 foot tanker vessel, has arrived in South Florida and will soon be sunk in late July as an artificial reef 1 ½ miles off Pompano Beach’s shore. This ship will be one of the biggest contributions to Florida's artificial reef system and one of the most easily accessible major dive sites in the nation. The ship will be the centerpiece of what will become known as Shipwreck Park, surrounded by 16 other existing wrecks covered with marine life. Shipwreck Park will be a unique underwater cultural arts park with rotating underwater art exhibits. The ship will include specific themes, exciting underwater events, artwork and rotating art exhibits to create a unique dive experience for local and international tourists.

This tanker ship which is longer than a football field was sold by the City of New York to The Shipwreck Park, Inc., a private 501 (C)(3) corporation, at a greatly reduced price. Shipwreck Park, Inc. has received sponsorship from the City of Pompano Beach and the Isle Casino Racing Pompano Park for the purchase, towing, cleanup, installation of artworks, and sinking of the ship. The ship was towed from New York to a facility on the Miami River for cleanup and installation of artwork before the sinking.

Pompano Beach artist Dennis MacDonald was hired to create several fun and unique underwater displays, including a casino theme for the ship deck. The art displays will include a swim-through cascade of gigantic dice, great for photo opportunities, as part of the Isle Casino Racing Pompano Park sponsorship.

The new Ventura is an extremely versatile BCD. This lightweight back inflation BC which weighs less than 5 lbs is fantastic for travel. But it is also a great BCD for local diving as well. Whether diving in Cozumel or Catalina the Ventura is designed from the ground up to be the best BC in class.

At only 4.7 pounds, it’s much more than the typical lightweight BC. The Ventura aircell is made of Double Coated TPU, which basically means it doesn't absorb any water and it doesn't gain water weight after repeated dives, a real plus when traveling. This Double Coated TPU material is extremely durable, and as a result we are able to increase the warranty on the bladder from Two years to Five years.

My first dive was in a murky lagoon in Key Largo, Florida. I bumbled along with a herd of excited new divers, stirring up the soft, oozing muck at the bottom of the lagoon. Diving was fantastic, but I didn't see much. For most of the dive, I was enveloped the brown cloud of bottom sediment that the divers had stirred up. Our finning technique, the flutter kick, was quickly reducing the visibility in the lagoon.

The flutter kick is an inefficient kick. It propels water above and below the diver, which does not contribute to forward motion and wastes energy. The downwards propulsion of water also disturbs sand and other bottom sediment, leading to a reduction in visibility. The frog kick is a much more effective kick, and is easy to learn with proper instruction. Click through this tutorial to learn the basics of the frog kick.

Our sea creatures are in trouble. What with warming temperatures, pollution, plastic debris and over-fishing, the oceans need protecting more than ever before. And governments are becoming more committed to creating marine reserves. But are they just paying lip service to the problem or really addressing it? Too often a marine reserve allows commercial fishing and other exploitation. A marine reserve which isn’t really a marine reserve at all.

The new IUCN Red List reveals that growing human pressures on whale sharks and slender hammerhead sharks are putting these species at an increasing risk of extinction. Both the shark species are now listed as Endangered.

Numbers of whale sharks (Rhincodon typus), the world’s largest fish, have more than halved over the last 75 years as these slow-moving sharks continue to be fished and killed by ship propellers.

Although conservation action in India, the Philippines and Taiwan has ended large-scale fishing of whale sharks in these countries, they continue to be fished in other locations, including southern China and Oman. As whale sharks and tuna are often found together, the sharks are frequently caught by tuna fishing boats.

Unregulated fishing is also behind the fast-falling numbers of the distinctive slender hammerhead shark (Eusphyra blochii), whose shape makes it easily get tangled up in fishing nets. This species has moved from Near Threatened to Endangered on the IUCN Red List.

Although it is difficult to say how many individuals remain, recent surveys of fish markets in Indonesia found only one slender hammerhead shark among approximately 20,000 sharks of other species. A similar pattern is expected throughout Asian countries where coastal fishing is intense and largely unregulated.

“It is alarming to see such emblematic species slide towards extinction,” says Jane Smart, Director of IUCN’s Global Species Programme. “These new IUCN Red List assessments emphasise how urgent it is for the conservation community to act strategically to protect our planet’s incredible diversity of life.”

A full update to the IUCN Red List of Threatened Species, including assessments of many other species, will be announced at the IUCN World Conservation Congress 2016 to be held in Hawaii from 1 to 10 September.

Whale sharks are found in all tropical and warm seas except the Mediterranean. The rise of dive tourism in many areas is making the fish more valuable alive than dead in some locations, including at Ningaloo Reef in Western Australia, Donsol in the Philippines, Placencia in Belize and Isla Contoy in Mexico. In all these places, and in other countries like the Maldives, India, Thailand and Malaysia, the whale shark is protected. However, the whale shark migrates long distances out of the safe areas and into the fishing zones.

It's a fact: we need oxygen to live. It's because of the way our cells use oxygen that we are able to breathe, exercise, and even think. In each of our cells, structures called mitochondria take the oxygen which diffuses in from our blood, disassemble it into its two component atoms (remember, oxygen - O2 - is composed of two oxygen atoms), and then hook some available hydrogen nuclei to them to form water.

The process releases energy, which is used for all functions of life. The problem is that in disassembling the oxygen molecule, it involves a step in which an extra electron is hooked on. This forms an intermediate called a superoxide anion, and this is a bad actor. It is highly reactive, and it will make mincemeat out of most other molecules it comes in contact with.

These anions are like coals in a furnace: as long as they are contained, we get lots of safe chemical energy; if they get out we get a great deal of damage. The mitochondria are designed to contain these superoxide anions, but just in case some get loose, there are a host of protective chemical reactions designed to sop them up and prevent them from doing any damage.

Besides producing excessive amounts of the superoxide anion, elevated tissue oxygen levels also affect a variety of other biochemical reactions which may affect oxygen toxicity in ways that are only beginning to be understood. Tissue-protective mechanisms and biochemical reactions are tuned to life in an atmosphere containing 21 percent oxygen, or 0.21 atmospheres absolute (ata) oxygen partial pressure. (See sidebar: "Remember Partial Pressure?", page 34.) As the partial pressure increases above this comfortable 0.21 ata, protective mechanisms are slowly overwhelmed and biochemical reactions are affected. This may eventually result in "oxtox," or oxygen toxicity.

As divers, we must adapt to an environment that exerts pressure on our bodies. The most common injuries reported to DAN each year involve pressure-related injuries to divers' ears and sinuses. A little education and common sense will go a long way to avoid these problems. Take a minute to read this page. DAN, your dive store and your instructor want your scuba adventures to be enjoyable and safe.

Sinus and Middle Ear Injuries

Barotrauma is a pressure-related injury. Middle ear barotrauma, known as "ear squeeze," is the most common diving injury. Sinus barotrauma also occurs, but is less common. How does it happen? Pressure changes when diving cause barotrauma. During descent, air spaces in the sinuses and middle ear must be able to equalize to the surrounding water pressure, which increases with depth. When pressure in air spaces can't equalize, the diver may sense pressure or pain from one of these areas. During ascent, if the expanding air can't be vented, the cavity pressure increases, resulting in discomfort. This type of injury can range in severity - from mild to extreme. A sinus or middle ear injury may occur suddenly and lead to inner ear damage. For this reason, divers should know and use the "clearing," or equalizing, maneuver that works best for them.

My experience with seasickness is that at first you are afraid you will die, then after a few hours you are afraid you will not.

Seasickness, or motion sickness, ruins diving trips, vacations and travel for many. Everyone is susceptible, and motion sickness can be produced in anyone if the circumstances are right. A lot is known about motion sickness, but total understanding of the cause is not clear. There are individuals who are resistant to motion sickness, but sufficient angular acceleration will induce motion sickness in anyone.

Even astronauts are annoyed by this problem. Approximately 70 percent of all crew members experience motion sickness of some degree during the first 72 hours of orbital flight on the space shuttle.

CauseIf you have experienced motion sickness, you probably think of it as primarily nausea. One theory says that this symptom is the result of your brain's inability to resolve the conflicting signals that it is receiving from the ears, eyes and body.

Scuba diving is a growing industry as a form of ‘nature tourism’ allowing enjoyment of the beauty of coral reef ecosystems. However, as the recreational diver population has increased, diving activities in some heavily dived sites have caused negative ecological impacts, with divers unintentionally contacting live corals and causing physical damage. In this research, we investigated the rate of divers' contacts and physical damage by observing divers' underwater behavior in Okinawa, Japan, and tested the effectiveness of pre-dive briefings as a mitigation measure. Of 105 divers observed, 7% contacted the live coral cover and caused skeletal breakage, and 91% made contact at least once but did not cause visible damage. The average contact frequency of the divers during 30 min of dive time was 0.53 times/min. The contact frequency of the divers decreased significantly after they listened to an environmental briefing among the divers who could maintain neutral buoyancy, but not in the divers who could not. This study suggests that buoyancy control training for divers may also be important for coral reef conservation in addition to environmental education.

The octopus is believed to be the most intelligent of all invertebrates. As well as its relatively large brain, each of the octopus’ eight arms has its own rudimentary intelligence. This allows the arms to function independently. Researchers think that the octopus evolved intelligence to help it hunt and elude predators.

In the wild, octopuses collect and manipulate objects. For example, octopuses have been observed arranging stones around the entrance to their dens. One octopus was captured on video using two coconut hulls as a makeshift suit of armour, holding the shells around itself and rolling along on the sea-floor like a ball. This has been construed as evidence of tool use.

Introducing Scuba Diving to Everyone I first met Cody at the No Barriers Summit in Park City Utah last summer. She and her team ran a series of adaptive scuba clinics at the summit, giving people with a diverse array of disabilities the opportunity to see if diving might be right for them.

From her stylish purple wheelchair she shared her passion for the sport with the enthusiasm and clarity that could only come from someone with her level of personal experience both as a diver and a woman with a disability.

Scuba Diving May Offer Relief to People With Disabilities Though Cody first took up diving as a hobby, she soon began to notice positive physical changes taking place under the water.While diving she felt more aware of the paralyzed parts of her body. These increased sensations lasted for a few weeks after a dive trip, but would soon fade.

The physical changes she was experiencing soon paired with her innate curiosity and drive to make a difference in the lives of other people with disabilities. She spoke with her doctors at Johns Hopkins hospital and convinced them that it was worth a scientific study.

In 2011 Cody traveled with a team of medical experts, adaptive dive professionals, and ten disabled veterans to the Cayman Islands to follow up on her idea. This pilot study found improved sensitivity and motor control in participants with paralysis and marked reduction in symptoms of Post Traumatic Stress Disorder in participants living with that condition.

As in Cody’s case, these improvements faded in a few weeks time. What the study accomplished was creating a clear scientific baseline that scuba diving might offer real physical and emotional relief for people living with a variety of disabilities. The Empowerment and Independence of Scuba Diving Cody’s personal philosophy stresses the joy and empowerment that occur while scuba diving. For people with disabilities the world can feel limiting. Scuba diving - especially for those with physical disabilities - offers an entirely novel environment to explore on their own terms.

The weightlessness of the ocean allows us freedom from the restriction of movement we feel on land. Underwater people with disabilities and their able bodied peers are all transformed into swimmers. The differences between wheelchair users and those who can walk disappear. This, combined with the feeling of accomplishment that all divers feel upon completing their adpative scuba certification is deeply empowering for people with disabilities.

To share these positive benefits with others Cody uses her foundation to raise money to plan trips and offer certification training to as many people with disabilities as they can reach.

Currently they are fundraising for a dive trip to Florida for a group of young people with Spina Bifida and Cerebral Palsy from the Riley Children’s Foundation in Indiana. If you are interested in making a donation they have a Go Fund Me campaign.

Get Involved With Adaptive Diving Aside from running her foundation, planning dive trips, and advocating for further medical studies of the effects of diving on people with disabilities, Cody has continued her studies both in and out of the water.

She is a PADI certified advanced open water diver, and is currently pursuing her Master’s in Public Health at George Washington University in Washington D.C. This year, she will be inducted into the Women Divers Hall of Fame for all that she has accomplished.

It is people like Cody Unser who advance the sport of adaptive scuba diving. She has created opportunities for dive professionals, medical researchers, and people with disabilities alike.

Her passion for diving and drive to include others in the adventure of it all are far reaching and profoundly positive. If you are interested in adaptive diving I urge you to look for opportunities to get involved and help continue to grow the positive impact that it has on the world.

Scientists in Australia have discovered that vinegar kills Crown-of-Thorns Starfish just as effectively as the current drug, which can be expensive and difficult to source.

Outbreaks of the venomous Crown-of-Thorns Starfish (Acanthaster planci) pose one of the most significant threats to the Great Barrier Reef.

Researcher Lisa Boström-Einarsson said vinegar had been tried unsuccessfully before, but James Cook University scientists refined the process which resulted in a 100% kill rate.

Ms Boström-Einarsson said the findings were exciting. “Currently divers use 10 or 12 ml of ox-bile to kill each Crown-of-Thorns Starfish (COTS). It’s expensive, requires permits and has to be mixed to the right concentration. We used 20 ml of vinegar, which is half the price and can be bought off the shelf at any local supermarket.”